Winter Pruning of Limes, Hazels & Dogwoods

Posted on January 14, 2023 by johnshortlandwriter

Hard pruning takes courage and gardeners are often reluctant to carry it out for fear of harming or, even worse, killing the plant. Once it is understood that more trees and shrubs are lost through neglect than by pruning the task becomes somewhat easier. In far too many gardens woody plants are grubbed out because they have outgrown their allotted space when judicious pruning at an earlier stage of their life would have allowed them to thrive and give pleasure for many more years.

*Outgrown its space? Don’t remove it, prune it!*

January and February are the perfect months for carrying out coppicing and pollarding and some shrubs like willow and dogwoods, grown for the winter colour of their bark, are actually improved by the process. Coppicing and pollarding are traditional techniques that have been carried out for centuries in woods and forests to provide a plentiful supply of fuel and fencing materials. As with all procedures, jargon evolves and coppicing and pollarding are just words that describe the removal of branches back to the tree trunk (coppicing) or, in the case of pollarding, the removal of stems to ground level. Somehow, if you just say to yourself, “cut off every branch” the mystery of the process disappears and becomes less intimidating.

*Willows – some newly pollarded line a riverbank*

Limes (Tilia) are very beautiful when grown as full-sized trees but become far too large for most gardens. They are better planted as parkland trees in a field, if you are lucky enough to own one, where there stature and grace can be appreciated from a distance. Too often they are grown where their branches overhang driveways where they drop their sticky honeydew over vehicles and become a nuisance. Most limes are host to tens of thousands of aphids (greenfly) which feed on its sap and then secrete the unwanted waste. Somehow, the gardener’s jargon word ‘honeydew’ sounds so much nicer than ‘greenfly crap!’ If you are determined to plant a lime tree in a confined space the Caucasian Lime, Tilia x euchlora which doesn’t have this problem is the one to go for. Remember that any tree in a confined space will need its size controlled so read on to find out how to pollard it.

*Limes, when mature, are beautiful but very large trees*

The time to pollard a tree is winter and January, when there isn’t too much to do gardening-wise, is the perfect month. I always aim to complete by the 31st which allows time to continue into February, if need be. By the middle of that month the sap will be starting to rise within the tree so it is sensible to complete the task by then. It is very straightforward to remove the branches for which you will need secateurs for smaller twigs, loppers for larger ones and a sharp pruning saw for anything bigger still. Which tool to use when? That too is easy to know. Secateurs and loppers should cut through the stems easily – if you need to twist the tool or the stem, you should be using the saw.

*By midsummer there is plenty of new growth on this old willow pollard*

Common sense will tell you that if you remove all branches from a tree there will be nothing left to offer any screening. This isn’t always important and coppiced trees send out new growth very rapidly as the weather warms up. However, for privacy or a different ornamental effect more careful pruning is required. All that needs to be done is to cut back any branch or twig that has grown beyond the space you have allocated for it.

*A pollarded lime allee provides drama and a focal point*

*This lime allee has had its side branches retained to give denser summer screening*

Limes are not often grown for the colour of their winter twigs probably as they are up rather high and so less noticeable. Willows (Salix) (when coppiced, for they can also be pollarded) and dogwoods (Cornus) are very different for their bright yellow, orange or scarlet stems are very visible and a mainstay for any winter garden. They are also quite simple to prune as it is all carried out at ground level. When the plants are mature, I prefer to cut them over a three year period as this retains their overall height. Quite simply, it means that only a third of the stems are removed or, if you have plenty of shrubs, completely prune one in every three to their base. The purpose behind this pruning is not so much to control their size but to maintain the strength of colour which is at its best on younger shoots. If left, they gradually become quite dull.

Hazels are treated very much like willows and dogwoods, although the usual purpose is purely to maintain a convenient size or to provide ‘pea sticks’ to be used for supporting summer plants as well as peas and beans. For guidance take a look at my earlier post from 2021 which can be read by clicking on the link here.

*A hazel tunnel is created by partial coppicing to reduce the number of tall stems*

The Chelsea Chop

Posted on May 23, 2021 by johnshortlandwriter

Despite its name, the Chelsea Chop isn’t the latest trend in hair styling although trimming the unruly and the straggly certainly is involved. It is a very simple and straightforward method of cutting back herbaceous* plants which, for some reason, terrifies even the most confident of gardeners.

*Sedums (foreground) growing at Lytes Cary Manor*

The only skills required are courage and the knowledge of exactly when to carry out the chop. The latter is simple to calculate and is hinted at by the title of the deed – the week of the Chelsea Flower Show or thereabouts. This year, there have been two hiccups in using this rule: firstly, the show has been moved to autumn because of Covid restrictions and secondly, because spring has been so slow in coming that plants are behind with their growth. As a general rule of thumb, the time for cutting is around the third week of May.

*The flat flowerheads of sedum are made up of hundreds of tiny star-like florets*

Beloved by bees and butterflies, Sedum – also known as Ice Plants on account of their fleshy, cool-to-the-touch leaves – are the ideal candidate for the chop and one of the most satisfying to do. Inevitably, when left to their own devices, the large, flat flowerheads are too weighty for their stems and they topple over to sprawl across the ground and spoiling an otherwise impressive display.

*Sedum, the Ice Plant, frequently collapses & looks ugly just as it flowers*

To make the chop all that has to be done is to cut through every growing stem, thereby reducing the plant’s overall height by half to one-third. Clear away the prunings (which can be added to the compost heap) so as not to attract slugs. There, I told you it was simple!

*Sedum given the chop. Don’t forget to pick up all the prunings!*

Although the method sounds and looks drastic the plants quickly recover and make new growth. The end result will be a plant that doesn’t collapse and doesn’t require staking. Admittedly, the flowerheads will be smaller than before but they produce so many more than they would have done left unpruned that the effect is in no way diminished.

*Numerous flowerheads appearing on the now tight growth of Sedum two months after the Chelsea Chop*

This simple pruning technique can be used on a number of other plants too in exactly the same way. The taller achillea, phlox, campanula, asters (michaelmas daisies) and rudbeckias are all good candidates. I have heard of its use on echinacea (cone flower), penstemon and helenium but, in my experience, these are trouble-free plants anyway, so why bother? The secret to good, stress-free gardening practice is to find the balance of what suits you and what suits the plant. The Chelsea Chop on sedum in May prevents an awful lot of stress later in the year!

*top left – clockwise: achillea, campanula, aster, rudbeckia. They can all be given the Chelsea Chop*

*herbaceous – a non-woody plant that dies back and becomes dormant in winter to regrow each spring

Old Yew, New Yew, Renew Yew

Posted on July 31, 2020 by johnshortlandwriter

Although in the UK the yew tree (Taxus baccata) is often called English Yew it is, in fact, very widespread in its distribution growing throughout Europe as well as parts of Africa, Iran and Asia. It can live to a great age and there are several, mostly growing in churchyards, that are thought to be a thousand or more years old. One such tree grows in the Chiltern village that I lived in before moving to the Cotswolds; it is enormous having a girth of over 5.5 metres. Despite being a British native that has grown naturally in the wild for thousands of years, yew woods are very rare – I can only think of two (although there must be others): one in the Chilterns behind Watlington Hill and the other in Sussex. One of the reasons for this is that yew was the favoured timber for making longbows – by 1294 yew stocks were so depleted that imports were being sourced from mainland Europe.

The yew forest at Kingley Vale, Sussex, England – one of the finest examples of this rare habitat in Europe [photo credit: Ben Shade]

The huge girth of the ancient yew in the churchyard at Ibstone , Chiltern Hills, England

Yew is unusual in that the individual plants can be male, female or a combination of the two. All-male trees release huge clouds of pollen whereas all-female produce none and can be identified by their glowing red berries. It has even been known for individual trees to gradually change sex with all-male specimens becoming all-female and vice versa. Although the pollen clouds can be extremely irritating if caught in one, in the average garden situation where mature trees are less likely to be found the pollen release is much more limited.

Swerford Park - Yew Berries(11) watermark

The glossy red flesh is the only part of yew that is non-poisonous. It’s still not advisable to eat it!

In its natural condition yew is a spreading, evergreen tree, wider than it is tall. However, for many centuries it has been clipped and shaped into hedges and topiary for which its regular, and when treated in this way, tight growth makes it ideal. It responds well to being kept low, say around 45cm, or can be stopped at any height required. Likewise, it can be clipped into neat cubes, intricate spirals as well as the ubiquitous peacock beloved by stately homes.

Yew topiary at Hidcote, Cotswold Hills, England

Intricate yew topiary at Farmleigh Gardens, Dublin, Ireland

One of the characteristics of yew is its ability to send out new growth from old branches and even from its trunk. This can be readily seen when the branches are parted or the main stems are exposed. To maintain a clean trunk these growths should be pruned away before they become established. With hedges and trees it means they can be reduced in size as drastically as you might wish although it is important to bear in mind that a heavily pruned tree may never be restored to a thing of beauty.

Yews ability to regenerate from old wood means that it can be pruned as hard as you dare

If reshaping trees is a skill difficult to master, restoring overgrown or gappy yew hedging only takes courage although for best results it may take a few years to achieve perfection. Begin this process by removing all growth back to the trunk on one side only. The hedge will now look ugly but new growth will soon sprout and the following year or in year three the other side of the hedge can be given the same treatment. Apart from the benefit this staggered pruning has to the health of the yew another advantage is that the screening from the unpruned side means there is no loss of privacy. The height of the hedge can also be reduced at the same time as side two cutting 6-12 inches below its required finished height to allow for regrowth. By year five, if not sooner, the hedge will be a manageable, healthy screen once more and will continue to be so for very many years.

The first stage in regenerating an old yew hedge

As with all plants, especially those that are long-lived, careful planting is essential to give them a good start. Yew copes with most soil types including chalk but hates waterlogged or compacted soils. Whatever the soil, enrich with good quality compost or well-rotted manure; if any parts are excessively damp create a low bank at least six inches high to ensure the roots establish in the marginally better drained soil. Pot-grown yews can be planted at any time of the year providing the ground isn’t frozen; the best time is mid-autumn and spring when the soil is warmer. The optimum size for quick establishment is 2-3 feet and this size also makes planting a hedge quite economic too. With a bigger budget larger plants may be purchased. These in the photo below are over six feet high and create an instant hedge when planted closely together. Because of their size they are usually ‘root-balled’ and only available during the cooler months. The hessian and wire mesh root ball should be left intact as they quickly decay once planted although the wire collar may be released if it fits too snugly against the stem. In windy situations they may require staking; they will certainly need careful watering for the first two years of their life.

Rootballed yew waiting to be planted – they will make a fine, if somewhat costly, instant hedge

However you chose to use your English Yew, whether as hedging or as topiary, there is one common rule to clipping and that is accuracy for nothing looks worse than a formal hedge or piece of topiary that does not have clean, sharp lines. The ideal time for clipping is August although spring is the time for restoration pruning. One word of caution – all parts of yew are highly toxic if ingested. It is essential that clippings are disposed of carefully for it can be fatal if livestock such as horses have access to them. Yew clippings from regularly clipped hedges can be sold for use by pharmaceutical companies to make cancer treatment drugs. In the past, when I was the Head Gardener of a large country estate with extensive yew hedging, we secured a not-inconsiderable amount of money over time which the estate donated to cancer research charities. I believe that, for 2020, collection has been suspended but hopefully it will be resumed in future years.

A beautifully clipped yew hedge creates the perfect backdrop to any garden – Kiftsgate Court, Cotswold Hills, England

Thinking Outside the Box(wood)

Posted on June 26, 2018 by johnshortlandwriter

Over the years I must have hand clipped many miles of box (in the USA, boxwood) hedging and once the knack is mastered it can be quite therapeutic. The main rule to follow is to remember that it has to be precise for there is nothing worse than a straight, level hedge that is clipped unevenly. It irritates the eye as much as a picture hanging crookedly on a wall.

Patience and plenty of time are key factors in ensuring straight lines

I can’t say that I feel quite the same about topiary. I can admire the craftsmanship that goes into producing weird and wonderful shapes but it is so easy, in a lapse of concentration to, say, cut the ear off a teddy bear or the beak off a peacock. As a consequence, I find it rather stressful. Cloud topiary is far more forgiving but, again, it doesn’t really “do it for me.”

You need even more patience to clip topiary

Perhaps the most rewarding design I have created was turning four rather scruffy and unbalanced squares of box into simple but elegant cubes. Yes, it was topiary but to misquote Star Trek “it’s topiary Jim, but…” To begin with, I was faced by the four squares each with a rather ugly and thorny shrub rose growing out of their centres. A consequence of this design was that the box couldn’t be clipped properly and neither could the rose be properly pruned.

The original design with roses always looked scruffy

To create the design the roses had first to be removed leaving a gaping hole in the centre of each square. Fortunately, I had some reasonably tall box plants elsewhere in the garden that I could dig up and replant. I soon discovered that it was impossible to plant them properly without damaging the existing plants. My gamble of just standing them on the earth and then throwing topsoil over them to trickle through the branches paid off. The soil covered the roots and probably much of the lower branches too*. Given a good watering, the plants thrived. Before trimming all the outer edges needed to be marked with string lines for accuracy in cutting.

Without strings for guidance clipping the box into perfect cubes would be almost impossible

I thought about all sorts of fancy designs for the tops of the cubes and, as is so often the case with design, I decided that simplicity was the key to a satisfactory outcome. Two cubes would have a raised circle and two a raised square. It was essential that these weren’t too high – I didn’t want them to look like a combination of wedding cakes and pimples! I found that it was impossible to mark these designs out and so they were created without guidelines, relying on my eye to tell me where and what to clip. By their second year of clipping they looked as if they had been there for ever.

Box hedge Clipping (10) Year 2 watermark

The design will look just as good in winter when highlighted by frost or snow

Box is such a versatile plant to use and it is well worth experimenting with them. Below are three photos of how I have used them: the first is the classic edging to a border; the second to bring focus to a set of garden steps; the third a mini-parterre to link two levels in a garden. Your garden doesn’t need to be huge or grand to use box in these ways – the parterre was suitably small scale for a tiny town garden. Have a go at creating your own box design – and if creating a topiary peacock is your thing, that’s fine with me – just don’t aske me to clip it!

The classic use for box – fronting a border

Giving focus to garden steps

Mini-parterre for a tiny garden

*This is also a good and easy way to create plenty of new plants for the buried stems will often send out roots. When they do they can be severed from the parent plant to be grown on elsewhere.